9.23. GRANT, REVOKE Statement
privilege_def : GRANT ALL PRIVILEGES TO grantee | GRANT privileges ON table TO grantee_commalist opt_with_grant_option | GRANT grantee_commalist TO grantee_commalist opt_with_admin_option ; privilege_revoke : REVOKE ALL PRIVILEGES FROM grantee_commalist | REVOKE privileges ON table FROM grantee_commalist | REVOKE grantee_commalist FROM grantee_commalist ; opt_with_grant_option : /* empty */ | WITH GRANT OPTION ; opt_with_admin_option : /* empty */ | WITH ADMIN OPTION ; privileges : ALL PRIVILEGES | ALL | operation_commalist ; operation_commalist : operation | operation_commalist ',' operation ; operation : SELECT priv_opt_column_commalist | INSERT | DELETE | UPDATE priv_opt_column_commalist | REFERENCES opt_column_commalist | EXECUTE | REXECUTE | role_name ; grantee_commalist : grantee | grantee_commalist ',' grantee ; grantee : PUBLIC | user ; user : IDENTIFIER role_name : IDENTIFIER
The GRANT and REVOKE statements are used to define privileges on resources to users and user groups (roles). A resource is a table, view or stored procedure. A grantee can be PUBLIC, meaning any present or future user accounts or a user name. Granting a privilege to a user name means that this user AND any users which have this user as their user group have the privilege.
Only a granted privilege can be revoked. The sequence:
grant select on employee to public; revoke select (e_review) from joe;
Is invalid because the privilege being revoked was not granted, instead it was implied by the select on all column to public.
Any role name created by the CREATE ROLE statement is a valid grantee and a valid grantable operation.
The term 'effective privilege of a user' means the set of privileges given to a user by virtue of 1. granting them to public 2. granting them to a role which is granted to the user or to a role either directly or indirectly granted to the user or 3. granting them, to the specific user. The dba user and all users whose group is 'dba' have all privileges.
GRANT ALL PRIVILEGES TO user;
is synonymous with setting the user's group to 'dba'.
The effective privileges inside a trigger are those of the owner of the table whose trigger is executing. The privilege of executing a trigger is derived from the privilege of performing the trigger action, e.g. update of a specific column.
The effective privilege inside a stored procedure is that of the owner of the procedure. The privilege to execute a given procedure is granted with the EXECUTE clause.
The grantee names are identifiers. This means that their case can be converted to upper case unless they are quoted. The identifier case conversion depends on the global CaseMode setting.
A user may grant or revoke privileges on resources of which he/she is the owner. A user with effective dba privileges may manipulate any privileges.
Example 9.40. Examples:
grant update ("Salary") on "Employees" to "Manager"; grant execute on "SalesReport" to "Accounting";
GRANT REFERENCES is a privilege required by a user on a table so that this user can create new tables referencing such tables in foreign keys where he/she would otherwise be restricted.
Remote SQL Data Sources. To provide
further consistent security to remote data, only the DBA group is
permitted to use the
unless explicitly granted. Caution is required here since any user
granted use of
rexecute() has full
control of the remote data source set-up by the DBA, however
limited to the overall abilities of the remote user on the remote
Users can be granted and denied access to
rexecute() using the following syntax:
GRANT REXECUTE ON '<attached_dsn_name>' TO <user_name> REVOKE REXECUTE ON '<attached_dsn_name>' FROM <user_name>
UDTs. Security of UDTs is maintained through normal SQL GRANT and REVOKE statements via a simple extension. You can define the level of access to both native and externally hosted UDTs. Grants for persistent user defined types are persisted into the SYS_GRANTS table. Grants on temporary user defined types are in-memory only and are lost (together with the temporary user defined type definition) when the server is restarted.
There are two GRANT/REVOKE types for UDTs as follows:
|EXECUTE - all methods and members of a class are accessible to the grantee.|
|UNDER - the grantee can create subclasses of the class.|
GRANT/REVOKE EXECUTE on <user_defined_type> GRANT/REVOKE UNDER on <user_defined_type>
SQL modules, user defined types and SQL stored procedures are exposed to GRANT/REVOKE in the same namespace, therefore care must be taken avoid inadvertently granting to multiple objects at the same time.